Assis-nos to inditstbial kegkaech cobpoha



H. R. DAVIES IGNITION SYSTEM Filed Feb. 21 1921 as :"E- n a 37%INVENTQR. "-5,- rlenry R Dawes ATTORNEYS.

Patented Oct. 20, 1925.

UNITED STATES PATENT OFFICE.

..L RESEARCH CORPORA- TION, OF TOLEDO, OHIO, A. CORPORATION OF DELAWARE.

IGNITION SYSTEM.

Application filed February 21. 1921.

To all whom it may concern:

Be it known that I. HENRY R. DAVIES a citizen of the United States,residing at Toledo, county of Lucas, and State of Ohio, have inventedcertain new and useful Improvements in Ignition Systems. of which Ideclare the following to be a full, clear, and exact description.

This invention relates to ignition systems for engines and hasparticular appliation to the non-seltstarting type of internalcombustion engines.

The invention has for an object the provision of means for generatingcurrent of approximately maximum pressure during the starting period ofthe engine.

A further object contemplated is the provision of means for increasingthe energy of the ignition circuit at engine starting which shall beentirely automatic in its action. I

Another object also is to establ sh a toll automatic speed adjustingignition system wherein the employment of movable or vibrating elementsare rendered unnecessary.

An important object is to provide a s stem wherein the starting voltageis approximately maximum and which decreases in a more or less uniformrate as the speed increases to an average value most. etiieient for thenormal running speed of the engine.

The invention further includes means for automatically decreasing thegradient of normal decrease of the voltage of the system as the speedincreases; and novel switch mechanism for effecting simultaneous closureof the ignition and motor circuits while permitting singular operationsof those circuits at opening.

Further objects, and objects relating to economics of manufacture anddetails of construction will become apparent as I proceed yvith thedescription of the various embodiments of my invention, which may bepreferred, illustrated in the accompanying drawings, in which Fi re I isillustrative of the invention a plied to a single unit dynamo-electricmac me normally operative either as a motor or a generator;

Figure II shows the invention .(pplied to a; two unit electric chargingan engine Serial No. 446.625.

starting circuit wherein a separate motor and separate generatoremployed, and:

Figure III illustrates a modification of the arrangement ot Figure II.

Referring to Figure 1 there is shown a storage battery 10, which isdesigned to furnish current when the engine is not running, for startingand lighting purposes. Connevted to the battery by means of maincircuits 11 and 12. through the manual switch 13, is a dynanm-electricmachine '14-. the field 150] which is connected in shunt around thedynamo-electric machine or starting generating dynamo, as it mayhereinafter be designated. adjacent the main brushes 16 and 17.

The starting generating" dynamo is illustrated as mounted on a shaft 15%which is operatively connecttul to an internal combastion engine (notshown). The starting generating dynamo is designed to transmit power asa. motor through the shaft 18 to start the engine and thereafter toreceive power from the engine as generator tor charging and li To obtainthese ends the e battery floated across the starting generating dynamomains as described above and possesses a voltage approxin rely equal tothe electric machine.

The ignition system shown oi the high tension type though any other typeof ignition would be equally usable in connection with the invention.The primary circuit is illustrated as containing the primary inductioncoil 19, interrupter contacts 20 and 21, interrupter arm 22, andcondenser 23 around the contacts 20 and 21.

One terminal 2 1 of the induction primary is connected through a switch25 to the main brush 16. The other terminal 26 is connected through theinterrupter and condenser to an auxilliary brush 27 which is operativelypositioned on the starting generating dynamo armature between the mainbrushes.

The secondary circuit of the ignition sys tem includes a high tensioninduction coil 28 connected to ground 29 at one end and connected at theother end through the distributing device 30 with its distributor arm 31and spark plug circuits 32. to ground 33. The distributor is connectedmechanicall to the engine power shaft through the shat 34, which also 0rates the interrupter cam 35 to open t e interrupter contacts againstthe resilient pressure of spring 36, which latter bears on theinterrupter arm 22.

It should be understood that the showing of the system throughout isdiagrammatical. The starting generating dynamo is illustrated as a bilar machine and merely the commutator is revealed but the variousmagnetic circuits, pole pieces and armature windings are conventionaland are here omitted. Further a four le machine would function asreadily in connection with the invention as the 2 pole machinerepresented. The secondary circuit 15 shown as disconnected from theprimary and a four cylinder sparking circuit indicated; but my inventionapplies as readily to a secondary connected to the primary at 24- andthen to ground rather than a direct ground, and any number of sparkingcircuits might be employed.

In the consideration of the operation of the embodiment of the inventionabove de scribed the various circuits and switches may be assumed to beinitially as illustrated in Figure I with the starting generating dynamoand engine in a state of rest. While in this state the lights 37 or anyother miscellaneous load may be supplied, through circuit 38 and switch39. with energy from the storage battery.

To start the engine the switches 25 and 13 are closed. These switchesmay be closed simultaneously as more clearly brought out in the modifiedforms of my invention hereinafter described. or successively, in whichlatter case preferably the ignition switch 25- should be first closed.

With switches 25 and 13 closed. current from the battery passes into thestarting generating dynamo circuits causing rotation of the armature inthe direction indicated by the arrow. It is a well known characteristicof dynamo-electric machines that when: operated as a motor the axis ofcommutation is shifted behind the neutral axis and when operated as agenerator the axis ofi commutation is shifted ahead, for a givenditnection of rotation. Since this distortion is due to the magneticinteraction of armature and field: it is evident that tor the shuntmachine. considered the maximum angle of lead or lag of the commutationaxis occurs for approximately maximum values of current, namely, whenthe motor is starting under load, or where the generator for a givenload is rotating at highest speed;

Assuming that the main brushes 16 and 1? are fixed near the neutral axisit is evident that for the direction of rotation indiouted and: forappropriate values and direction of field flux and current there will amaximum value of voltage between brush 16 and auxiliary brush 27 atstarting which voltage willprogressively decrease as the startinggenerating *dynamd' begins to generate current and its loadcurrentincreases. On the other file load current in the generatingstarting generating dynamo decreases the voltage between brushes 27 and16 increases. .75 The characteristics above described are' utilized byconnecting the ignition circuit to the auxiliary brush 27 and main brush16 a! previously indicated. This results in the highly advantageouseffect of obtaining maximum voltage in the ignition circuit at: startingwhen fuel condensation effects in the engine are most disadvantageouscarburetion relatively ineflicient. In my Patent Number l,3 72,650patented: March 22, 1921, I have illustrated the application of thebroad features of this invention to a starting generating dynamo whereinboth the field and ignition are connected 3 to an auxiliary brush andamain brush,.between which the voltage decreases with speed thus securinga relatively rapid cumiilative decrease of voltage in the ignition cuit.This arrangement is particularly advantageous in automotive tractionunits} which are subject to continuous variat'ion of} speed; but forsome uses particularly 128%,

plied to stationary units, 1' have found arrangement as illustrated in Figure A with the shunt field connected directly across the main brushes.to be more advant us, since the gradient depends almost on the armaturereaction variable This? gives a more uniform and less rapid decrease ofvoltage during the generating period of r the starting generating d namewithout in any way impairing the e 'ciency of the ma chine at startin yIn Figure 11 Thave ill'ustrated' amcdifi cation of my invention as a.plied to 'two unit system, wherein two ynamo e1 Iii; machines, onenormally functioning, as a generator and the other as a motor, rsusediThe battery 10 su plies the. liglflfi h through circuit 38 an switch39as previously described arrangement. q Any type of suitable startingmotor It) be utilized but I have illustrated far-1t purposes of thisinventiona sari type motor 50 mounted on a five shaflfl W operativelyconnected with the engine to; 1]} started. One main brush 52 is conn,

54 and the other main brush.55. is connected through the field 53 o onebattery fie a nal 5 The generator 58 is shown as a shunt machine mountedon an engine I nected shaft 59. Thereare twomainh through the switch 56to the batteiystannn 60and 61 and an auxiliary brush 62nd" h a. 1 A..rjrna iesmaanak hjumjuu .4

xiinuaam a man; His.

shunt field 88 is connected to the auxil ary brush 62 and the main brush60.

T he generator is connected in parallel with the motor to the battery,the brush ill ha ving a closed circuit. with battery terminal 5- and themain brush (St) is in circuit with the battery terminal 57 through aplurality of switches. I

One of these switches. broadly indicated as 65, is automatic inoperation being adapted or closure by the magnetic action of a shuntcoil (34. on a movable armature contact arm "i5, which arm carries acontact (56 registerng with a corresponding stationarv contact $7 in thegenerator circuit. The arm (i?) has permanent electrical connection witha coil 438 also magnetically related to the contact armature 65 and inseries with the main circuit from the generator brush (50 to the battery terminal 57.

The function of this switch 3 is to close the contacts (36 and 67 whenthe voltage of the generator has acquired a predetermined value suitablefor charging the battery it) and to open the contacts 66 and 6? when thegenerator voltage has decreased to a point where the combined magneticeffects of both shunt coil 64 and series coil 68 fails to main tainclosure against the retractive action of spring (as, an arrangementpreventing contact chattering.

The switch 70 has a manual contact arm 71 adapted to effect closure ofthe main generator circuit and also of the ignition circuit as will behereinafter set forth. The arm 71 is designed to move freely in a slot72 cut in an operating handle 73 fixed to the motor switch arm 5(3.spring 'i"-l tends to maintain the switch 56 in a normal open positionas indicated in the drawing and in this position switch 71 may be eitheropened or closed because of the slotted connection to the handle 73.However with both switches in open position as illustrated closure ofswitch 56 will also simultaneously cause closure of switch 71 which dualclosure will remain effective until pressure on the handle 73 isremoved, when the switch 56 opens leaving the switch 71 closed.Subsequently the switch 71 may be opened either by a continued upwardmovement of the handle 73 or by direct manipulation of the switch arm.

The ignition unit is similar in all respects to that described inconnecton with Figure I. The primary circuit includes the primary iii--duction coil 5. contacts 76 and 77. contact arm 78, spring 79 andcondenser 80. The secondary circuit includes the grounds 81v and 82secondary coil 83, distributor arm 84. and spark plug circuit contacts85. The shaft 86 operates the interrupter cam 87 and the distributor arm84.

One terminal of the ignition circuit is connected to the auxiliary brush62 and the other terminal is connected to the main hattor circuitheti'veen the switches 633 and 70. When th Sa'fliCil 63 closedtherefore. both the generator field 88 and ignition are con neeted inparallel to the hrushes and subjected to the same armature reactive etiec in tlcscribinu the operation oi the system illustrated in ..igiiie itmay be assumed that the engine is at rest and the various i- ,'it '-hesin the po:' ons shown. Compressing the s it) closes the motor circuitand a circuit n the battery terminal 111 '71 primary igniature windingsand brush .3 c to batt terminal 'Ilhereupon the ig :i-on devices andmotor are energized and the engine starts up under its own power.

As the engine speeds up the directly connected generator builds up avoltage which closes the switch 63 at approximately the battery voltage.Current then passes from the generator through the switches 63 and T0 tothe battery and charging of the same begins. Simultaneously on theclosing of the switch 63, ignition current is supplied the ignitionsystem from the generator.

The particular tures of the arrangement of Figure ll are that currentfor ignition is initially supplied as battery voltage and with noarmature reactive effects. but that as soon as the generator functions,which is very shortly utter the engine is started, a cumulativelyvarying voltage gradient dependent on at least two variables is present.One of these variables is th main line voltage which is diminished withincrease of speeds because of armature reaction. therehv affecting thevoltage oi the ignition circuit. The second variable is the generatorvoltage on the ignition circuit which diminishes with increase oigenerator or engine speed or with increase of load as indicated withreference to Figure I. These factors combine to produce a relativelyrapid voltage drop characteristic on the ignition circuit, subsequent toclosure of the automatic switch.

The arrangement oi Figure IT has been found iiarticularlv acvantaecouswhen used in connection w th small capacity batteries subject to more orless continuous charging conditioi'is such as occur in automotivevehicle or railway cars. Under high speed conditions charging proceedsat a n'iininnun rate and may in tact entirely cease the auto maticswitch breaking the circuit. Similaz ly at low speeds the switch ("13atitoniaticalh opens. But between the extremes of speed the switch 63 isclosed and the generator Furnishing ignition and cliarp ii'ig current.the charging current being of course most etlective. at the lower speedranges. In this way gvercharging of the battery is prevcntet.

tion circuit.

Ill)

In the modification of Figure III the same units and circuits areutilized as shown in Figure II with the addition, however, of aresistance coil 90 in the primary ignition circuit.

The obfect of the resistance 90 resides in the necessity in someinstances of providing in a system such as illustrated in Figure IImeans for diminishing the ignition voltage in the lower generator speedranges without at the same tim correspondingly decreasin the ignitionvoltages at the higher speer ranges to an inefficient value. Aresistance coil with a high temperature coefficient such as iron has ifproperly designed relatively high resistance for large current but smallresistance for small currents: and the use of such a device tends toflatten out the ignition voltage curve at lower speed ranges withoutdiminishing the effectiveness of the high speed ignitionand armaturereactive influences described in reference to Figure II.

I am aware that the specific embodiment of my invention herein describedand illustrated are subject to variation without dcparting from thespirit of the invention. and, therefore, I desire to claim the samebroadly as well as specifically as indicated by the appended claims.

I desire to claim as my invention:

1. In an ignition system for gas engines. the combination of adynamo-electric machine having main brushes and an auxiliary brush; ashunt field connected to the main brushes: an ignition circuit connectedto the auxiliary brush and one of the main brushes: a storage batteryconnected to the ignition circuit and to the dynamo-electric machine forsupplying current to the dynamo-electric machine to operate the same asa motor, and to receive current from the Y is increased.

2. In an ignition system, the combinatiofl f of a dynamo-electricmachine having a, oom i mutator, main brushes. and an auxiliary" brushbetween said main brushes a shunt field connected to the main brushes ofdynamo-electric machine and an ignition ctrcuit having one terminalconnected to of said main brushesand the other tcrminol connected'to theauxiliary brush, the voita of the machine between the wuxiiiary br andthat one of the main brushes to which. the ignition is connected,tending to dimin-fj ish with increase of machine speed.

3. In an ignition system, thecomhination fl of a dynamo-electric machinehaving main brushes and a third brush; a shunt fish; a.

. i 4. The combination of a dynamo-electric l! machine, having a fieldcircuit: an ignition. circu t: and means dependent on armature reactionfor diminishing the voltage on ignition circuit only asthe mach'me speedi In testimony whereof, I aflix my sigma? ture.

HENRY R. DAVIES;

